Imaging optics, in particular as projection optical units as part of projection exposure apparatuses for microlithography are known from EP 1 093 021 A2, DE 10 2005 042 005 A1, US 2006/0284113 A1, US 2006/0232867 A1, EP 1 450 196 A1, EP 1 452 899 A1, EP 1 806 610 A1 and U.S. Pat. No. 6,213,610 B1.